Aurora assessing risk after falling tree sparks fire in Alexandra

Fire crews in Alexandra check the scene after a fire that was caused by a tree falling on to a power line near Jolendale Park earlier this month. Aurora Energy is now looking at the design of the line that goes through the park to reduce future fire risk. P

A power line that caused a fire in Bridge Hill in Alexandra earlier this month is being given "high priority'' by Aurora Energy as the line is assessed to reduce future fire risk.

About 75sqm of vegetation near the boundary of the 6ha Jolendale Park was burnt in the February 4 fire, which Aurora Energy operations and service delivery general manager John Campbell said was caused by a tree falling on to a power line.

There had been concerns from some in the community and at a recent Vincent Community Board meeting that the fire had been caused by a power pole falling down or failing of other Aurora infrastructure.

However, Fire and Emergency New Zealand Alexandra Senior Station Officer Derek Shaw confirmed no power pole had fallen.

Mr Campbell said a high voltage overhead line had fallen to the ground after a tree fell and contacted the power line.

"The line would have been live on contact with the ground and that energy would have sparked the fire.

"On making contact with the ground, fault protection operated and tripped the power off.''

Mr Campbell said a pine tree was found on the ground at the location of the downed wire, parallel to the high voltage overhead conductors.

"The pine tree had been growing in rocks and for some reason, we suspect wind, it broke and contacted the power line.

"We will never know, but it could have been weakened in the severe weather event several weeks prior and the wind on the day caused it to fall to the ground.

"For clarification, there was no pole down and the insulator was not a contributing factor.
"Again, for clarification, we had received photos of fuses and tape at the bottom of a pole; these were most likely placed there temporarily while repairs were being carried out and [were] not a factor in the incident.''

Vincent Community Board member Dr Barrie Wills, who raised his concerns about the fire during his member's report at the board's last meeting, said cadastral maps showed the fire was on Aronui Reserve land, near the boundary of Jolendale Park.

Mr Campbell said the section of line where the fault occurred was "with our design team, who are looking at what needs to be done to reduce the risk of fire in future. This is a high priority for us''.

Several other trees under the power line would be cut down to stop them contacting the overhead line, he said.

Dr Wills said he was still concerned about the fire and was "sceptical'' about the "tree falling on the line'' explanation.

Mr Campbell said other measures Aurora took to manage summer fire risk included turning off "automatic reclosing''.

"That means after a fault trip we only turn the power back after a line inspection and repairs have been completed, which is what happened in this instance.''

pam.jones@odt.co.nz